<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<style>
button {
  position: absolute;
  border: 1px solid blue;
  margin: 1px;
  padding: 0;
  writing-mode: vertical-rl;
}
div {
  position: absolute;
  background: yellow;
}
</style>
</head>
<body>

<button style="top:0px"><img src="" width="20" height="80"></button>

<button style="top:100px"><img src="" width="80" height="20"></button>

<!-- solid-color <div>s that should completely cover the buttons above,
     provided they size themselves properly for their <img> content -->
<div style="top:0px; width:40px; height:90px;"></div>

<div style="top:100px; width:100px; height:40px;"></div>

</body>
</html>
